Metallurgical furnace



Feb. 21', 1928. 1,659,869 A. M. Gow Y METALLURGICAL FURNACE Filed June 1'7 1921 Jlexazder/K 6050, amf

yPatented Feb. 21, Y1928. j j VUNITED STATES "PATENT OFFICE'.

ALEXANDER M'. GOW, 0F DULUTH, MINNESOTA; AMERICAN EXCHANGE NATIONAL BANK OF D'UL'U'TH EXEOUTOR 0F SAID ALEXANDER M. GOW, DECEASED.

METALLURGICAL nommen.

application mea :rune 17, 1921. Vseran no. 473,260.

This invention relates to'a metallurgical furnace of the t pe using gaseous fuel, and more particularljr to a method and means for producing a higher flame temperature and more rapid combustion of the gas in such furnaces.

In furnaces of this character it is the usual practice to admit the air and gas alternately at the opposite ends of the furnace. Because of the large volume required and the large volume of the products of combustion, the ports are necessarily of very considerable cross-sectional area. The air and gas ports are located adjacent each other, the air port usually being superimposed upon the gas port. The two Vports are usually separated by a refractory arch which not infrequently is water-cooled. In the usual construction the water-cooled end of the arch terminates' at about the end of the melting chamber. By this form of construction the air enters in a more or less flat layer the width of the air port, while the gas enters in a similar, although usually narrowerlayer below the air. No provision is ordinarily made for insuring or positively forcing the two layers to mix, it being assumed thatthe lighter gas will graduallyl rise through the air. This interrmxture takes place but slowly however, and the effective flame does not begin until well into the furnace from the port ends. Y,

The flame temperature is much lower than would be the case if the mixture of airand gas had taken place in a mixing chamber before it entered the melting chamber of the furnace.

It is an object of the present invention to provide new and improved means for causing the mixture of the air and gas before their entrance into the melting chamber, and further to cause this mixture without any reduction in the usual area of the ports, or other interference with the usual passage of the gases and air.

It is a further object to provide means of this character which requires but a small amount of power and which may be applied to existing installations at relatively small expense and without material alteration of existing structures. v

Other and further objects will appear as the description proceeds.

Broadly, my invention consists in the introduction into the air or gas streams, or

' both, of a jet or jets of air or oxygen under relatively high pressure. These jets serve to force the streams into each other and to cause the intermingling of air and gas. J ets may be provided above serving to force the air down into the gas, or below serving to force the gas up into the air or in both places. They may be so disposed as to 'give a swirling motion to the combined stream of air and gas, with consequent effective intermingling of the two components. The volume of this air under pressure may be very small compared to the total volume of air and gas. The number and location of the jets will depend somewhat upon the size and design of the furnace. Preferably, the usual water-cooled gas port is reduced in length so that a mixing chamber is formed between the end of that port and the melting chamber. The air at high pressure will normall not be as hot as the preheated air into w ich it is introduced and hence a small reduction of temperature occurs; but due to the relative quantities of the compressed and preheated air this cooling is relatively slight and is very much more than compensated for by the increased efliciency of combustion. This reduction of temperature is much less than would be caused by constructions involving the water-cooled dampers or the like which have been proposed for the purpose of directing the preheated air and gas streams to ether.

y invention is admirably adapted for use with the richer gases containing hydrocarbons such as coke oven gas or natural gas. Such gases must be broken down into their constituents, carbon and hydrogen, before combustion takes place. Heat and time are required to effect this breaking down but it is impractical to heat such gases in regenerators because of the deposition of carbon. By causing the immediate intermingling of such gases with the heated air by the means of my high pressure jets, the gases are broken down in the mixing chamber and the furnace without deposition of carbon and in ideal condition for complete combustion within the chamber. Obviously some combustion will take place immediately the gas and air come into Contact in the preliminary mixing chamber. This preliminary combustion will augment; the temperature of the gases before their entrance into the melting chamber and complete combustion will take place therein lll at a very high temperature. The amount of this preliminary combustion will de end Iing by controlling the velocity and volume of the high ressure 'ets. This .may, of course, be rea 'ly done y valves or similar means.

Under certain circumstances it may be desirable, instead of 'air to use either air -so 'combined with oxygen as to materially v increase the oxy en content, or possibly even pure oxygen. i uch jets .will not vonly .mix the air and gas but will aid very materially in the :combustion and increase its temperature.

I have illustrated a preferred embodiment of my invention in the accompanying drawing, 1n which the single ligure shows a vertical longitudinal section through one end of an open hearth furnace equipped wlth my invention. f l

The furnace as shown comprises the melting chamber 5, mixing chamber 6, air port 7, air uptake 8, air slag pocket 9, also the gas port 10 gas uptake 11, and gas slag pocket 12. Ihe gas port 1s surrounded by the water-cooling element 13. A pair of nozzles 14 and 15 are placed respectively above and below the entrance from the mixing chamber 6 to the melting chamber'. A similar nozzle 16 is provided at the upper side of the air port and a nozzle 17 below the discharge end of the gas port. As shown, these nozzles are all connected to pipes by which they are provided with com prllessed air, or oxy en, as has been stated.` ese nozzles may e provided, if desired, with water-cooling elements or otherwise `formed so as to protect them from heat in any desired manner. The provsion of such means,.however, forms no part of the present invention and need not be further described herein.

The gas comes up through the slag pocket'12 and uptake 11 and out'through the port 10. The preheated air comes from the checker chamber (not shown) through the slag pocket 9, uptake 10 and out of the port 7 which straddles the gas port. These two streams of gaseous fluld are caused to mingle by' the introduction of the high pressure jets from the' several nozzles. If desired, the nozzles may be used selectively, the nozzles 14 and 16 when used alone serving to force the air current downwardly into the gas current and to cause the mixed'ow of a1r and gas to pass through the lower part of thefurnace; In the same manner, if it is desired to have the flame at a higher level in the furnace, only the jets 15 and 17 may be used. When all jets are used a more thorough intermixture will be secured, but

any one of the jets very materially increases the intermixture vof'the lair and lgas, and' any particular .furnace and construction.

I claim:

conduits for low pressure air and gas leading to a furnace chamber, and compressed air conduits havin opemngs so located as to force an intermixture of the air discharging from the air conduit and the gas discharging from the gas conduit. j v

2..In a furnace, adjacently located large conduits for low pressure air and gas leading to a furnace chamber, and compressed air conduits havingopenings located adjacent the dischar e opening of the air conduit u on they side thereof op osite the openin o the gas conduit whereby the compresse air is adapted to force the air into the as.

3. In a furnace, adjacently locate conduits for air and gas leading to a furnace chamber, andcompressed air conduits having op'enin located adjacent the dischar e opening o the gas conduit u on the side thereof opposite the opening o the air conduit whereby the com ressedair is adapted to force the gas into tliie air.

4. In a furnace, a large gas port, a large air port superposed on said gas ort, said ports being adapted to discharge arge volumes of air and gas under low pressure and compressed air conduits each having a downwardly directed small opening adjacent said air port, the compressed air discharge therefrom being adapted to force the air from the air port to `intermingle with the gas from the gas port.

5, In a furnace, a gas port, an air port superposed on said gas port, and compressed air conduits each having an upwardly directed opening adjacent said gas port, the compressed air discharged therefrom being adapted to force the gas from the gas port to intermingle with the air from the air port.

6. In a furnace, a gas port, an air ort superposed on said gas port, compresse air conduits having upwardly directed openings and other compressed air conduits having downwardly directed openings adjacent said ports whereby the compressed air discharged from said openings causes the air and gas issuing' from said ports to be intermingled.

7. In a furnace, adjacently located large conduits for lo'w pressure air and gas leading to a furnace chamber, and compressed air conduits having o enings of comparatively small area adapte to so discharge air under relatively high pressure as to cause an inter- 1. In a furnace, adjacently located large,

lpositions' according tothe requirements of n mingling of the air and gas discharged from said large conduits.

f8. In a furnace, a melting chamber, gas and air ports discharginglarge volumes of low pressure gas and air toward said melting chamber into a mixing chamber intermediate said orts and melting chamber, and compressed) air conduits having openings adapted to discharge jets of compressed air into said mi'xin chamber whereby the air and gas from sald ports are intermingled.

9. The method of mixing gas and air in furnace operation which consists in causing a premixture of large volumes of low pressure gas and air by the use of jets of air at relatively high pressure.

10. The method of mixingV gas and air in furnaceoperation which consists in introducing large volumes of air and gas at low velocity in adjacent streams and"directing jets of air at relatively high pressure againstV said streams whereby they are caused to intermingle.V

Signed at Duluth, Minnesota, this 11th day of June, 1921.

ALEXANDER M. GOW. 

